Basel, COUNCIL OF (1431–43), the last of the three great reforming councils of the 15th century, was summoned by Pope Martin V., and opened under his successor Eugenius IV., 23d July 1431. Its first session was held at Basel on 14th December 1431. Instead of the method followed at Constance, where the members deliberated and voted by nations, the council was divided into four departments, each with its own organisation, and each investigating a special class of subjects, its decision and reasons being communicated to the others. If three agreed in their opinions, the matter was brought before the whole council for final discussion and judgment. In this way the influence and intrigues of the Italian bishops were neutralised. The council addressed itself to the reconciliation of the Hussites, and to the reform of abuses in the church itself. But the first attempt to conciliate the Hussites was met with resistance by the pope, who not only refused his sanction, but empowered the cardinal legate to dissolve the council. The council strongly repelled the pope's pretension of right to dissolve it, and proceeded with its business. His injunctions that it should remove to Italy were equally disregarded. It renewed the decree of the Council of Constance, asserting the right of a General Council to exercise authority over the pope himself, and on his persevering to issue bulls for its dissolution, caused a formal process to be commenced against him, and cited him to appear at its bar. It assumed the papal powers, and exercised them in France and Germany, where its authority was acknowledged. It concluded a peace, in name of the church, with the Calixtines, the most powerful section of the Hussites, by the Prague Compact of 20th November 1433, granting them the use of the cup in the Lord's Supper. At length, Eugenius IV., being hard pressed by insurrections in the States of the Church, and afraid of losing his whole influence in France and Germany, solemnly ratified all its decrees, by a bull dated 15th December 1433. Desirous, however, of limiting the papal prerogatives, the council restricted the power of granting interdicts, abolished annats and other grievous exactions, and prohibited the bestowal of reversions to ecclesiastical offices. It also appointed punishments for certain immoralities in the clergy, and prohibited Festivals of Fools, and all the indecorous proceedings which had been commonly practised in churches at Christmas; and it adopted decrees concerning the election of popes, and for the regulation of the College of Cardinals.
At this time, a prospect was opened up of the union of the distressed Greeks with the Church of Rome, and a council was proposed to this end. The Basel fathers refused to meet in Ferrara, and having again cited the pope to its bar, not only, on his failing to appear, declared him contumacious, but on his opening an opposition council at Ferrara, went so far as, on January 24, 1438, to decree his suspension from the functions of his office. His party, however, was so strong that this decree could not be carried into effect; and the cardinal legate, with the greater number of the Italians, left Basel, and went over to his side. All the more resolutely did Cardinal Louis Allemand, Archbishop of Arles, a man of high courage and eloquence, now guide the proceedings of the council, which on May 16, 1439, declared the pope a heretic, for his obstinate disobedience to its decrees; and in the following session, formally deposed him for simony, perjury, and other offences. On November 5, 1439, it elected Duke Amadeus of Savoy to be pope, who styled himself Felix V., but was recognised only by a few princes, cities, and universities. France and Germany accepted the reforming decrees of the council, but remained neutral in the question regarding the popedom. The friendship of the Emperor Frederick III. strengthened the party of Eugenius; and the council gradually melted away, and its members, after three years of inactivity, held its last session at Basel on May 16, 1443, and removed its seat to Lausanne. Here a few prelates still remained together under the presidency of Cardinal Allemand, till in 1449, after the death of Eugenius, and the resignation of the antipope Felix, a compromise was effected, by which the fathers directed the church to obey the new pope, Nicholas V., who in return confirmed the acts of the council. Thus ended the last attempt to reform the church from within, and on its old basis. The Basel reforming decrees are contained in no Roman Catholic collection, and are held to be invalid by the canonists of Rome; yet they are of authority in canon law in France and Germany, although their application has been modified by recent concordats. See vol. vii. of Hefele's Konzilengeschichte (Freiburg, 1869).